英文:
QUARKUS - MicroProfile REST Client: add a custom, not mapped field
问题
我正在遵循这篇文章 https://quarkus.io/guides/rest-client 来构建一个REST客户端，以解析来自restcountries.eu服务的输出。
这里是保存模型的类：
public class Country {
public String name;
public String alpha2Code;
public String capital;
public List<Currency> currencies;
public static class Currency {
public String code;
public String name;
public String symbol;
}
}
现在，假设我想要添加自定义字段，比如时间戳，以记录创建该对象的时刻。我想象中，我会继续添加另一个字段，如下所示：
public class Country {
public String name;
public String alpha2Code;
public String capital;
public List<Currency> currencies;
public Instant timestamp; //<--------- 添加的属性
[...]
我的问题是：我如何告诉客户端填充那个字段？通常，我会在构造函数中完成。然而，我找不到解释这部分的文档。
谢谢您的帮助，
Simone
英文:
I am following this article https://quarkus.io/guides/rest-client to build a REST Client to parse the output from the restcountries.eu service.
Here the class holding the model:
public class Country {
public String name;
public String alpha2Code;
public String capital;
public List<Currency> currencies;
public static class Currency {
public String code;
public String name;
public String symbol;
}
}
Now, suppose I would like to add a custom fields such as timestamp, to record the instant when this object has been created. I imagine, I would go ahead and add another field like below:
public class Country {
public String name;
public String alpha2Code;
public String capital;
public List<Currency> currencies;
public Instant timestamp; //<--------- added attribute
[....]
My question is: how do I tell the client to populate that field? Normally, I would have done it in the constructor. However, I could not find docs that explain this part.
Thanks for your help
Simone
答案1
得分: 1
你实际上可以在默认构造函数中执行此操作。像 JSONB 或 Jackson 这样的框架希望POJO具有默认构造函数。在创建Country实例时，它们会调用它。
使用 @JsonbTransient 或 @JsonIgnore 注解来标记你的POJO中的属性，以便避免解组器对在响应中找不到的属性发出投诉。
@Data
public class Country {
private String name;
private String alpha2Code;
private String capital;
private List<Currency> currencies;
@JsonbTransient // 如果你使用的是 JSONB（在 Quarkus 中是默认的）
@JsonIgnore // 如果你使用的是 Jackson
private Instant timestamp;
public Country() {
this.timestamp = Instant.now();
}
PS：@Data 注解是你应该考虑使用的。封装并不是一件坏事，但创建getter/setter很繁琐。然而，Project Lombok 在这方面确实很有帮助。
英文:
You can actually do this in the default constructor. Frameworks like JSONB or Jackson expect POJOs to have a default constructor. They will call it when they create an instance of Country.
Use the @JsonbTransient or @JsonIgnore annotations to mark that attribute of your POJO as ignorable in order to avoid the unmarshaller complaining about attributes that cannot be found in the response.
@Data
public class Country {
private String name;
private String alpha2Code;
private String capital;
private List<Currency> currencies;
@JsonbTransient // if you're using JSONB (default in Quarkus)
@JsonIgnore // if you're using Jackson
private Instant timestamp;
public Country() {
this.timestamp = Instant.now();
}
PS The @Data annotation is something you should consider using. Encapsulation is not a bad thing but creating getters/setters is tedious. But Project Lombok certainly helps here.
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